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Discussion Starter #1 (Edited)
I was considering ordering the Signal dynamics Heads-Up Voltage Monitor for about 30 bucks.

I know that with my electronics background I could build one cheaper, so I was browsing my local electronics supply store for parts when I happened to come across this sitting in the isle with all the build it yourself kits.
http://www.vellemanusa.com/products/view/?id=525836

I grabbed it and took it home since it was cheap and gave it a test.

Here are the rough voltage results:
red: battery voltage is low (below 10.8 volts)
green: battery OK (10.8-12.95 volts)
Slow pulsing (green): battery OK or charging (12.95-14.8 volts)
red blinking: battery is being overcharged (above 14.8 volts)



The LED is tiny, can be easily seen in daylight, but not overly bright, which is fine with me since I don't need to be blinded at night by a blinking LED pointed at my face.

It works well enough for what it is intended to do, which is give me a quick heads up if the charging system is not working properly.

I plan on un-soldering the LED and soldering a set of wires between the LED and the PC board. I picked up a LED holder and will be mounting the LED on the dash as suggested in other posts. The PC board will get wrapped in rubber tape or heat shrink and fastened either in the headlight bucket or some other inconspicuous place. The 2 wires to power the logic board will be wired in to the driving lights so it will be off when the ignition is off.

For about half the price of the Signal Dynamics version, I am glad I found this little gem. I will post pics once the install is done.
 

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So basically it says that when your bike is running, and your R/R is pssing volts to your battery...i.e. "charging" your battery, it will blink green....as long as the voltage is between 12.5 and 13.5 volts.


Sorry but if your getting only 12.5 volts, your battery is NOT charging. A bad stator can still show 12.5-12.7 volts. So you can have a malfunctioning stator and the light will blink green telling you nothing is wrong. Many times the bike will put out over 14 volts....and no, the battery is NOT getting "overcharged"..

Spend the extra money and get a usefull gauge. One that actually has a digital readout that tells you exactly how many volts are going to your battery being the best pick.

Sorry.
 

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Discussion Starter #3 (Edited)
The voltages posted were what I was seeing on a quick and dirty test, which is why I used the word "rough". I will test it on the bench tomorrow and report what my findings are. Either way, I can adjust the trigger voltages for each output change of the LED.

I regularly check voltages with a good quality digital meter during warm up of the bike to see what is going on. The intent of this LED is to just give me a "heads up" if something is not functioning normally.
 

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Well that be different if you can fine tune each voltage range for each indicator.

I do like the fact there is only one light and not a bank of them as some LED units I have seen.

Still rather just have a simple digital readout. No guess work ...;) 13.8 volts means 13.8 volts....
 

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Discussion Starter #5
Revised Voltages in first post....ok..so the initial test was way off

compare to Signal Dynamics heads up voltage monitor output specs:
Flashing Red - Below 12 VDC
Steady Red - 12.1 - 12.5
Steady Amber - 12.6 - 12.8
Steady Green - 12.9 - 15.24
Flashing Green - Voltage Above 15.25 VDC

Velleman battery monitor MK189:
red: battery voltage is low (below 10.8 volts)
green: battery OK (10.8-12.95 volts)
Slow pulsing (green): battery OK or charging (12.95-14.8 volts)
red blinking: battery is being overcharged (above 14.8 volts)

I like the simplified scale and colors/flashing just seem to make more sense IMHO
 

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Signal Dynamics Heads Up voltage monitor Is a good product. Like mine just fine. And a good place to mount the LED in through the back/top of the light bucket. With the limited space, I'd be more out to put an oil pressure gauge on before a volt gauge. As long as it's green you have battery juice. All we have for oil pressure is a light and that don't tell you what oil your internals are getting.
 

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oil pressure guage

Signal Dynamics Heads Up voltage monitor Is a good product. Like mine just fine. With the limited space, I'd be more out to put an oil pressure gauge on before a volt gauge. All we have for oil pressure is a light and that don't tell you what oil your internals are getting.
Is there any way possible to add a guage to the VN750 ?
WilliamTech
 

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I have a (believe it or not) digital voltmeter mounted to the handlebar clamp with double sided tape. Being digital, and plastic, I don't know how long it will last, but I've had it for over a year. How accurate it actually is I don't know, but the display is very accurate, using four numbers, it measures voltage to the hundredths. I have it connected directly to the battery, to get the most accurate reading. Being digital, it has the same issue I find so distracting with digital multimeters, it constantly fluctuates, and when it does, it's not a tiny barely visible movement of the needle, but a complete change in numbers. However, it is entertaining to watch the last 2 numbers keep changing up and down as it idles, and watching all the numbers change as you ride it through town. Once you get used to it's readings, you would quickly notice a difference if they changed very much. I think I paid about $30 for it online.
 

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Discussion Starter #9 (Edited)
I installed the battery monitor today. I installed the LED on the dash just to the left of the ignition switch. Ran the 3 LED leads to the headlight bucket (through one of the harnesses). I wrapped the PCB up with rubber tape to insulate and also covered it with electrical tape and stuffed it in the back of the headlight housing. I tapped into the dash lights and wired it up. Buttoned it up and tested everything. I am happy with the install and with the performance of the monitor.

With ignition on(bike not running) and at idle it stays lit green.
At 2K RPM and above, the LED flashes green.
I turned off the engine with the kill switch and left the lights on to see if it would stay lit green, which it did. I see that when the starter is engaged and the bike cranks the engine, the LED will after a few tries turn to red, but only if you really stress the battery.








I am happy with this circuit, and although it doesn't display a voltage, I can get a general idea if the system is working. For me that is just some peace of mind after constantly reading posts about failed charging systems. If I am cruising and that little LED isn't Flashing green, then I know not to shut down the bike until I am somewhere safe....hopefully home.
 

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I recommend that along with a device to monitor the battery voltage, that you put an "off" switch in the headlight circuit. I already have one, which I installed so that I could turn the headlight off (in the daytime) if the battery voltage dropped too low while using my electric gloves. This could also be used to save power if the charging system failed. The headlight uses way more power than anything else, and there is no reason to waste that power if you are running the ignition off the battery alone. Also get and carry another key, so you can fill up the gas tank with the engine running, and avoid having to use the starter. A fully charged battery will power the ignition system for over 1000 miles.
 

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Discussion Starter #11
just an update...this battery monitor already paid for itself when my original stock battery finally decided to give up.

The battery(acid filled wet cell now 6 years old) was testing good and was maintained on the battery tender Jr. when not being driven. I knew it was way past it's life cycle and I intended to replace it this spring anyway. I tend to test the battery with my voltage meter every so often and it appeared to be ok.

I was driving home from work and it was indicating that the charging system was doing it's thing at highway speeds. When I hit the side roads approaching home and had to stop at red lights and intersections, I started to notice the battery indicator flash red if I sat for a few minutes with brake and blinker lights on. I decided to head straight home rather than make a few stops as planned. When I got home, I left the bike running and checked the system with my digital meter. The charging system was working fine, but the battery was draining rather quickly. The battery was not holding a charge.

If I had not been given an indication that something was wrong, I may have continued to drive along and possibly gotten stranded somewhere. I can only imagine that constant high demand for battery charging a weak battery, added to normal demand for running the electrical system eventually would have stressed the R/R or and possibly caused it to fail. Even worse would be taking out the stator...I shudder to think of the consequences.

I changed out the battery with a new Deka AGM battery, and all is well again :smiley_th
 

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Discussion Starter #13
Shame shame on you for running a wet cell that long. Don't you read all the info on this forum??....lol.
you are absolutely correct! I just wanted to get through the winter before changing out the battery. Who'd a thunk it was going to be such a nice riding season in "Winter"??

I am surprised that the battery lasted 6 years!! I was trying to go for a record....lol. I will say this...the pickup mod along with iridium plugs helped with hot starts even with a crappy battery. Now that I have the Deka AGM installed it starts with just a blip of the start button. The bike is starting and running better than it has since it was new.
 
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